The "white smoke" description sounds most like a blown head gasket. You will need to check things like see if the engine oil is contaminated with antifreeze, run the car with the antifreeze reservoir cap removed and watch for gas purging, pull spark plugs and look into the cylinders to see if antifreeze is present (or remove spark plugs, disable ignition system and turn engine over while watching for antifreeze to spray out of the spark plug holes. There are also some repair shops that have a chemical additive that they add to the antifreeze and then run an exhaust gas analysis to detect the chemical additive (tells them that a corruption of the cooling system by the piston/cylinder/cylinder head region has occurred. My guess is that you will be able to determine blown head gasket by checking the oil, pulling plugs, or running with antifreeze reservoir cap removed. The exhaust gas should smell like antifreeze if the gasket or worse is shot.

Let's say you determine at a minimum that the headgasket could be shot. The cylinder head has to be pulled and checked for warpage. I don't know the Ford spec but the usual rule of thumb is that an overhead cam engine can tolerate no more than 0.002" warpage; greater warpage means replace the head because the cam will likely bind-up in its bore. Look at the cylinder walls. If the engine has been severely overheated, the walls will be scored. If they are scored, replace the engine.

And we haven't even gotten to the root cause of the overheating yet...

Dave Keller
1995 Contour SE (No mods, yet)